The Gauss Gun
AND THEN…they pulled out the Gauss Gun. And we, teachers and scholars alike, were all blown away. You get some neodymium magnets, a few ball bearings, and a groove on which the ball bearings can roll. A single ball bearing (from the left) is given a gentle push toward the magnet. As the single ball approaches the magnet, it feels the magnetic attraction, gets pulled in, and suddenly…the rightmost of three balls on the opposite side ROCKETS away with unexpected velocity (usually causing first-timers to jump in surprise).